/**
 * 
 */
package com.lanswon.qzsmk.base;

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

	public class ListPageUtil<T> {
	    /**原集合*/
	    private List<T> data;
	 
	    /** 上一页 */
	    private int lastPage;

	    /** 当前页 */
	    private int nowPage;

	    /** 下一页 */
	    private int nextPage;
	//    
	    /** 每页条数 */
	    private int pageSize;

	    /** 总页数 */
	    private int totalPage;

	    /** 总数据条数 */
	    private int totalCount;
	    
	    public ListPageUtil(List<T> data,int nowPage,int pageSize) {
//	        if (data == null || data.isEmpty()) {
//	            throw new IllegalArgumentException("data must be not empty!");
//	        }
	 
	        this.data = data;
	        this.pageSize = pageSize;
	        /*this.totalPage = data.size()/pageSize;
	        if(data.size()%pageSize!=0){
	            this.totalPage++;
	        }*/
	        
	        this.nowPage = nowPage;
	        this.totalCount = data.size();
	        this.totalPage = (totalCount + pageSize - 1) / pageSize;
	        this.lastPage = nowPage-1>1? nowPage-1:1;
	        this.nextPage = nowPage>=totalPage? totalPage: nowPage + 1;
	        
	    }
	 
	    /**
	     * 得到分页后的数据
	     *
	     * @param pageNum 页码
	     * @return 分页后结果
	     */
	    public List<T> getPagedList() {
	        int fromIndex = (nowPage - 1) * pageSize;
	        if (fromIndex >= data.size()) {
	            return Collections.emptyList();//空数组
	        }
	        if(fromIndex<0){
	            return Collections.emptyList();//空数组
	        }
	        int toIndex = nowPage * pageSize;
	        if (toIndex >= data.size()) {
	            toIndex = data.size();
	        }
	        return data.subList(fromIndex, toIndex);
	    }
	 
	    public int getPageSize() {
	        return pageSize;
	    }
	 
	    public List<T> getData() {
	        return data;
	    }
	    public int getLastPage() {
	        return lastPage;
	    }

	    public int getNowPage() {
	        return nowPage;
	    }

	    public int getNextPage() {
	        return nextPage;
	    }

	    public int getTotalPage() {
	        return totalPage;
	    }

	    public int getTotalCount() {
	        return totalCount;
	    }

	   public static void main(String[] args) {
	        Integer[] array = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12};
	        List<Integer> list = Arrays.asList(array);
	 
	       // ListPageUtil<Integer> pager = new ListPageUtil<Integer>(list, 10);
	        ListPageUtil<Integer> listPageUtil = new ListPageUtil<Integer>(list,4, 5);
	        List<Integer> pagedList = listPageUtil.getPagedList();
	        System.out.println(pagedList);
	    }
}
